Effects of Spatial Patch Characteristics and Landscape Context on Plant Phylogenetic Diversity in a Naturally Fragmented Forest

Abstract

Phylogenetic diversity is a reliable predictor of taxonomic and functional diversity and of biodiversity option value. During forest fragmentation, forest patches that vary in size, degree of isolation, and shape are formed. Identifying the spatial characteristics of forest remnants that maximize phylogenetic diversity could be useful to conservationists when prioritizing areas to be protected if resources are limited. In this study, we assessed whether spatial patch characteristics (size, edge density, and shape) and the context of the patch in the surrounding landscape (i.e., isolation degree) affect plant phylogenetic diversity in 19 naturally shaped forest patches. Owing to the age of the forest patches, the study system allowed us to assess the long-term effects of spatial variables on phylogenetic diversity. We found that patch size has a positive effect on phylogenetic diversity, presumably because environmental heterogeneity and niche opportunities are greater in bigger patches. Also, phylogenetic diversity was positively affected by edge density. The convergent evolution of traits which confer tolerance to prevailing edge conditions in phylogenetically distant species may explain this result. We suggest that patch size is a reliable predictor of plant phylogenetic diversity and could be used as a prioritization criterion in conservation strategies, at least in the study area.